Paperboard cartons are typically formed from rolls of paperboard which are cut into "blanks." Score lines are scribed between sections of a blank to divide the blank into rectangular sections and to facilitate folding of these sections with respect to one another. In forming a carton from the blank, a top, side, or bottom panel of the carton is initially left unsealed so that the carton may be filled with a product through the unsealed panel. Different equipment is typically used to fill the carton, depending on the panel which is left unsealed; "side-fill" equipment is used to fill a carton with an unsealed side panel, "top-fill" equipment is used to fill a carton with an unsealed top panel, and "bottom-fill" equipment is used to fill a carton with an unsealed bottom panel Once the carton is filled with a product, the carton is sealed and the filled carton is ready to be sold to a consumer.
With respect to powdered detergent applications, most detergent companies use "top-fill" equipment or "bottom-fill" equipment to fill powdered detergent into cartons prior to sealing the cartons. In order for a detergent carton design to be compatible with existing filling equipment, it is advantageous for the detergent carton to be constructed with the appropriate panel left unsealed so that the carton may be filled through the carton top or bottom.
In a variety of consumer packaging applications, not only is it advantageous to supply cartons or containers which are compatible with typical industry "filling" equipment, but it is also important to supply cartons which are capable of being conveniently, yet securely, opened and reclosed repeatedly. The ability to be repeatedly opened and closed down in a lockable manner is particularly important where the carton is used for storage of granular or powdered material, such as laundry detergent powder.
An exemplary recloseable carton design uses a carton lid which hingedly attaches to a back panel of a carton base. An integral tear strip is generally used to permit the opening of a carton which has been packed with the appropriate material and subsequently sealed. The lid is separated from the base by removing the tear strip and lifting the lid up. Subsequently, the carton is reclosed by pushing the lid back down to its original position.
Conventional recloseable cartons of the above-identified type suffer from disadvantages which severely restrict their use in certain consumer packaging applications, particularly where the packaged product constitutes granular or powdered material such as concentrated laundry detergent powder or the like. The present inventor has discovered that a major drawback in this regard is the general absence of a positive locking arrangement in combination with a carton design which is conducive to repeated open and reclose operations. More specifically, the previously discussed exemplary design has been found to be undesirable in certain applications because of the likelihood of the lid opening and leading to spillage of the contents thereof when such a closed carton is tipped over or otherwise disposed at an acute angle.
The present inventor has also discovered that such recloseable cartons can be improved by providing some form of positive indication, either tactile or audible, of the fact that an opened carton has been reclosed adequately in order to realize an effective locking position It has been determined in this regard that the presence of such tactile or audible feedback indicative of effective locking is desirable because the presence thereof provides consumers with a high "comfort" factor with respect to reclosure. Particularly in applications where the recloseable cartons are used to house granulated material having a restricted storage life once the storage container has been torn open, such positive feedback has bee determined to provide an apparent sense of reassurance to consumers as to retention of "freshness", "safety", or scent of the contained product.
Accordingly, there exists a distinct need for a recloseable, flip-top carton design which overcomes disadvantages of the above type associated with conventional recloseable paperboard cartons. The present invention effectively and conveniently realizes such a recloseable carton design.